Many structural materials found in nature incorporate a large fraction of minerals to generate the stiffness and hardness required for their function (structural support, protection and mastication). In some extreme cases, minerals form more than 95% of the volume of the material, as in tooth enamel or mollusk shells. With such high concentrations of minerals, one would expect these materials to be fragile, yet these materials are tough, durable, damage-tolerant and can even produce ‘quasi-ductile’ behaviours. For example, nacre from mollusk shells is 3,000 times tougher than the mineral it is made of (in energy terms) and it can undergo up to 1% tensile strain before failure, an exceptional amount of deformation compared to monolithic ceramics. The question of how teeth, nacre, conch shell, glass sponge spicules, arthropod cuticles and other highly mineralized biological materials generate such outstanding performance despite the weakness of their constituents has been pre-occupying researchers for several decades.
Accordingly, it would be beneficial for brittle materials to be modified into tough/deformable materials. The inventors have established that the introduction of well-designed interfaces within the same material can completely change its mechanical response. In this manner, the inventors have established that brittle materials, for example glass the archetypal brittle material, can be engineered into a tough and deformable material.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.